Simultaneous fractionation of two crude oils



Feb. 7, 1967 M. F. PoTTs ETAI.

SIMULTANEOUS FRACTIONATION OF TWO CRUDE OILS Filed Deo.

United States Patent 3,303,127 SIMULTANEOUS FRACTIONATION F TWO CRUDE OILS Mack F. Potts and Frank E. Johnson, Bartlesville, Okla., assignors to Phillips Petroleum Company, a corporation of Delaware Filed Dec. 4, 1964, Ser. No. 415,978 9 Claims. (Cl. 208-355) This invention relates to a method and apparatus for fractionation.

Heretofore, when it was necessary to treat at least two crude petroleum materials the products from each of which materials are sufliciently different to require them to be recovered separately from one another, a separate fractionation operation including related stripping operations on the distillates formed was employed on each separate crude petroleum material. Thus, for each crude petroleum material treated a complete and separate fractionation system was utilized which is not only quite expensive due to the duplication of -apparatus but is also inefficient since the amount of crude petroleum material passing through each separate fractionation system inevitably varies. Due to such variance, when the amount of material being processed by a particular fractionation system is at a minimum value, as is often the case when more than one fractionation sys -tern is being used, that system is not operating at the optimum load for which it w-as designed.

It .has now been found that at least two crude petroleum materials at least part of whose products should remain separated from each other can be fractionated in a very eflicient manner utilizing ya single fractionation zone and a single flash zone both of which zones are interrelated in a specific manner. Thus, by this invention the necessity of separate, distinct but identical fractionation systems for each separate crude petroleum material lto be treated is eliminated and replaced with a single, simpler, more efllcient and less expensive fractionation system.

According to this invention there is provided apparatus for and a method of combined fractionation of at least two crude petroleum materials the heavy components of each of which materi-als cannot be combined without deleteriously affecting the valuable properties of the heavy components of at least one of the above materials. For example, if the heavy components of one mate-rial have a high wax content they should not be combined with heavy components from another material that are good asphaltic material due to their low wax content.

The method of this invention comprises fractionating at least one of the crude petroleum materials in a single fractionation zone to produce a gasoline fraction, a heavy gas oil fraction, a topped crude fraction and at least one diesel fuel fraction and flashing at least one of the other of s-aid crude petroleum materials in a single flashing zone to produce a reduced crude fraction and a light gas oil and lighter fraction. The light gas oil and the lighter fraction from the flashing zone is passed into a lower portion of a fractionation zone in order to combine the light gas oil and lighter m-aterials of all of the crude petroleum materials being treated since they can be combined without any deleterious effects.

The heavy gas oil fraction from the fractionation zone is passed along with the crude petroleum material fed to the flashing zone to supply additional gas oil to the ICC flashing zone and thereby maximize the amount of gas oil removed from the flashing zone along with the reduced crude residual product of said zone since the reduced crude product of the flashing zone is weil suited for further treatment by catalytic cracking and the like for the formation of lighter hydrocarbons such as gasoline. There is then recovered from the fractionation zone a topped crude product substantially free of heavy components present in the crude petroleum materials which were charged to the flashing zone, and diesel and lighter fuel fractions which contain components from al1 of the crude petroleum materials charged to both the flashing zone and the fractionation zone. There is also recovered from the flashing zone a reduced crude product which is substantially free of heavy components present in the crude petroleum materials which were charged to the fractionation zone.

It has also been found that a more efficient and more precise combined fractionation is achieved if at least one of the diesel fuel fractions separated in the fractionation zone is removed and passed to a v-apor removal zone wherein the lighter vaporous materials associated with the diesel fuel fraction are separated from the liquid diesel fuel portion. The vaporous portion is then removed and returned to the fractionation zone and the now vapor-free liquid portion is in part cooled and returned to the fractionation zone below the withdrawal locus of lthe diesel fuel fraction as reflux. The remaining part of the liquid portion is passed to a stripping zone to vaporize residual materials that are lighter than the desired diesel fuel product land the vaporized lighter materials are returned to the fractionation zone. The thus stabilized liquid diesel fuel portion is removed from the stripping zone as a product of the fractionation operation.

It has further been found that an even more efiicient and precise combined fractionation is lachieved when at least one diesel fuel fraction from the above fractionation operation, preferably from the above stripping op eration, is treated to form hydrogen sulfide from the sulfur compounds present in the feed, and to also form some gasoline boiling range hydrocarbons. The eflluent from the hydrogen sulfide producing operation is subjected to a flashing step to remove hydrogen and the remaining effluent is charged to a stripping zone in which the produced hydrogen sulfide and the produced gasoline components associated with the diesel fraction are vaporized. The vaporized hydrogen sulfide and vaporized gasoline components are then removed from the stripping zone, the hydrogen sulfide separated from the gasoline components, which also contain some diesel fuel components, by condensing the gasoline-containing stream and the gasoline-containing stream returned to the fractionation zone above as at least a portion of the reflux therefor, and for subsequent recovery therefrom sep- -arately of gasoline components and of diesel components.

Thus, it can be seen that an eflicient and precise fractionation operation is carried out on a plurality of crude petroleum materials with a single complete fractionation system the result of which is the combination of those components of the crude petroleum materials which are compatible and the production -as separate materials of those components of the crude petroleum materials which are not compatible when blended since product specifications cannot then be met, and therefore must not be combined in the final product.

Accordingly, it is an object of this invention to provide a new and improved method and apparatus of fractionation. It is another object of this invention to provide an improved method and apparatus for the combined fractionation of at least two crude petroleum materials, e.g. crude oils, which fractionation combines compatible materials while maintaining incompatible materials separate from one another.

Other aspects, objects and the several advantages of the invention will be apparent to those skilled in the art from the description and the appended claims.

The drawing shows diagrammatically a system embodying this invention.

In the drawing a low wax content asphaltic crude oil is passed by 1 to a desalting operation 2, to remove inorganic salts from the crude material so that these salts will not be present to cause plugging of heat exchangers, corrosion of the apparatus, and the like. operation also provides for the removal of arsenic and other trace metals which act as poisons to catalysts subsequently used on various fractions of the crude oil. Conventional desalting operations are applicable to this invention and known in the art. For further details see Petroleum Rener, volume 39, No. 9, September 1960, page 257. The desalted crude oil then passes by 3 through heater 4 and 5 into fractionation'zone 6 wherein the crude oil is separated at least into a gasoline fraction, at least one diesel fuel fraction, a heavy gas oil fraction and a low wax content topped crude fraction. The gasoline fraction is removed from 6 by 7 and treated in a manner to be described. A heavy diesel fuel fraction is removed from 6 by 8 and passed to a stripping zone 9 which is heated by steam from 10 to vaporize and strip light components from the liquid, and the light vapors are removed from 9 and passed by 11 back to 6. The stabilized heavy diesel fuel fraction having thus had lighter components removed therefrom will meet flash point specifications for such a diesel fuel is removed from 9 by 12 for storage, further processing and-the like. A lighter diesel fuel fraction is removed from 6 by 31 and treated in a manner to be described. The low waX content topped crude fraction is removed from 6 by 13 for storage, further processing and the like, e.g. to vacuum distillation to produce specification asphalt products. The heavy gas oil fraction is removed from 6 by 14 for further treatment to be described.

A high waX content paraffin crude material is passed by to desalting zone 16 for treatment similar to that described with respect to desalting zone 2 and then by 17 through heater 18 and by 19 into flash zone 2.0. The heavy gas oil fraction in 14, the flow of which is controlled by flow controller 21 which is operatively connected by 22 to an orifice means upstream in 14 and by 23 to motor valve 24 downstream in 14, is added to the parain crude in 19 and introduced therewith into Hash zone 20. Steam is supplied to flash zone by 25, the flow thereof being controlled by flow controller 26 which is operatively connected by 27 to an orifice means upstream in and by 28 to motor valve 29 downstream in 25. The temperature and pressure in 20 is maintained at values such that light gas oil and lighter material are vaporized and removed from 20 by 30 and passed into fractionator 6. Line 30 contains gas oil components separated from both crude oils, along with components lighter than gas oil, which lighter components are present in the parailnic crude oil charged to flash zone 20. The gas oil components are removed from zone 20 in order to insure that substantially all of the components lighter than thegas oil are separated from the parafiinic crude and passed to fractionator 6 by way of 30 for recovery, ultimately, by lines 7, 8 and 21, and to insure that substantially none of these lighter components is removed in the reduced crude in 32.l Line 14 removes from fractionator 6 not only the gas oil components added thereto from the'paraflinic crude oil in 15 `by conduit 30, but

The desaltingV also the gas oil components removed from the asphaltic crude oil in 1. The high wax content reduced crude product in 32 recovered from parainic crude oil in 15 contains not only the gas oil components originally present in crude oil in 15, but also contains the gas oil components recovered from the asphaltic crude oil in 1. The reduced crude in 32, fortified with gas oil components and cooled by 33 is Well suited for further processing such as catalytic cracking, catalytic hydrocracking, and the like. The rate of ow of reduced crude removed from the system through 34 is controlled by liquid level controller 35 on flash zone 20 which controller is operatively connected by 36 to 4motor valve 37 in line 34. The reduced crude product from 34 due to its generally high wax content is not suitable for combination with the generally low wax content topped crude from 13 since the high wax content will yield asphaltic products which will not meet specification requirements such as the Oliensis Spot Test and the ASTM Ductility Test (77 F., 5 cm./sec.). That is to say, the high wax content of the reduced crude willyield a positive result in the Oliensis Spot Test and a Ductility Test of less than 100 cm. and therefore is unsuitable for use as an asphaltic product. Thus, it cannot be combined with the topped crude in 13. The reduced crude is, however, due to its high gas oil component content and its own complex hydrocarbon composition, Well suited for further conversion operations such as catlytic cracking to form therefrom additional high octane gasoline components and other distillate products such as isobutaneand light olens which can be utilized for alkylation, polymerization, synthetic rubber preparation and the like. Thus, it is highly desirable that` the reduced crude and topped crude be maintained separate from one. another, but in order to simplify the fractionation system from both the technical and fiscal point of View it is highly desirable that a single precise fractionation zone be utilized to separate those lighter fractions such as gasoline, diesel` fuel and the like, from both the asphaltic and the paraflin crude. Such is achieved by the above-described combination of single complete fraction zone and single flash zone.

The light diesel fuel fraction removed from 6 by 31 is passed to vapor removal zone 38 which accumulates and holds the continuous flow of diesel fraction liquid, containing light hydrocarbons, from 31 for a time sufficient to allow the lighter portion to separate as vapor from the liquid portion and collect in an upper area of zone 38. The separated and collected vapor is removed from 38 by 39 and returned to 6 as `vapor by 40. The semi-stabilized liquid diesel fuel portion is removed from 38 -by 41 and a part passed by 42 to pump 43, and a part passed by 44 to stripping zone 45. Since the liquid in 42 has had the lightest vapors separated therefrom, it is well suited to be passed through pump 43 because the absence of light vapor therein minimizes the chances for cavitation to occur in the pump. The liquid from pump 43 passes by 46 through cooler 47 and then `by 48 eitherl through 49 to 3-way motor valve 50` or through 51, cooler 52 and 53 to motor valve 50 or both. From motor valve 50` the liquid passes by 54 to fractionation zone 6 at a point below the withdrawal locus of 31 to be utilized as reflux and to keep the area `below the withdrawal locus of 31 at a preselected temperature which is sufliciently below that of the withdrawal locus to prevent heavy hydrocarbon components from reaching that locus and thereby insuring that the diesel fuel fraction Withdrawn at that locus meets the percent distillation point requirements, and thereby helps the diesel fuel fraction meet specification requirements. The flow of liquid through motor valve 50 is controlled Iby temperature controller 55 which is operatively connected by 56 to a downstream temperature-sensing means in 54 and by 57 to motor 'valve 50 upstream in 54.

f Motorvalve 50 is adjusted to operate in a manner such that in order to meet the set point temperature in temperature controller 55 warmer liquid from 49 and cooler liquid from 53 are continuously mixed in varying quantities to produce a composite stream with a temperature equal to the set point. The ow of composite liquid through 54 to 6 is controlled by flow controller 58 which is operatively connected by 59 to an orifice means upstream in 54 and -by 60 to motor valve 61 downstream in 54.

That part of the liquid diesel fuel fraction in 41 which passes through 44 to stripping zone 45 is heated, by stripping steam introduced by 62, to a temperature such that the remaining light components in the diesel fuel fraction, similar but slightly higher boiling than those removed by 39, are vaporized and also removed along with the stripping steam by 63, passed to 40 and thereby returned to 6. The removal of lighter components in stripping zone 45 insures that the flash point requirement land front end distillation requirements for diesel fuel of the type and for which the diesel fraction is intended to 'be used are met, thereby helping the diesel fuel fraction meet specification requirements. It should be noted that due to the prior removal of substantial amounts of vaporous material by vapor removal zone 38, a substantially reduced load is placed on stripping zone 45 thereby allowing that zone to make a more precise removal of lighter components than would otherwise be possible with a savings of stripping steam. The ow of liquid through 44 to stripping zone 45 is controlled by liquid level controller 64 on zone 45 which is opera-tively connected by 65 to motor valve 66 in 44. Thus, for example if the liquid level -in 45 should exceed a predetermined maximum value the liquid level controller `64 would pinch down motor valve 66 thereby decreasing the -amount of liquid passing through 44 to zone 45.

A liquid diesel fraction is removed from stripping zone 45 lby 67 through cooler 68, line 69, pump 70, line 71, heater or furnace 72 and line 73 into desulfurization zone 74. The -ow of liquid through 71 to zone 74 is controlled by ow controller 75 which is operatively connected to an orifice means by 76 upstream in 71 and by 77 to motor valve 78 downstream in 71. Zone 74 is a conventional operation, such as hydrodesulfurization, for the removal of sulfur, nitrogen and metal compounds, primarily for the removal of sulfur as hydrogen sulfide. In the case of hydrodesulfurization, hydrogen-rich gas is heated with the diesel fuel fraction to form hydrogen sulfide. For further details see Petroleum Refiner, volume 39, No. 9, September 1960, page 250. The efiiuent from desulfurization zone 74 passes after cooling, not shown, by 175 to a flash zone 176 wherein gaseous reactants such as hydrogen are flashed off and removed by 177. The effluent is removed from flash zone 176 by 178 and passed through heater 79 and line '80 to stripping zone 81. The flow of efliuent through 178 is controlled by ow controller 82 which is operatively connected to an orice means by 83 upstream in 178 and by 84 lto motor valve 85 downstream in 178. Flow controller 82 is lalso operatively connected by 86 to liquid level controller 87 on flash zone 176. Thus, for example, flow controller 82 has a specific flow set point at which to maintain motor valve `85. Liquid level controller through 86 is adapted to reset ow controller 82 to a new specific flow set point if the liquid level in fiash zone 176 should exceed the predetermined maximum or fall below a predetermined minimum. Thus, for example, should the liquid level in 17 6 exceed the predetermined maximum value liquid level controller 87 will reset liow controller 82 to a new higher ow set point and dow controller 82 will then further open motor valve 85 so that the flow through 178 will be substantially equal to the new higher iiow set point.

. Stripping zone 81 is maintained at a pressure and a temperature sufficient to vaporize iand/ or effect separation of sulfur compounds such as hydrogen sulfide and light components such as gasoline components along with an equilibrium quantity of diesel fuel components which vapors are then removed by 88, partially condensed by `cooler 89 land passed by 90 into accumulator 91. Ac-

cumulator 91 is maintained at a temperature and a pressure such that the hydrogen compounds such as hydrogen sulfide remain in the vaporous form and the gasolinecontaining stream is in the liquid form. The vaporous hydrogen sulfide is removed from 91 by 92 for storage, further processing, and t-he like. The rate of removal of the sulfur compound is controlled by pressure controller 93 which is operatively connected by 94 upstream in 92 and by 95 to motor valve 9'6 downstream in 92. The liquid lighter hydrocarbon components are removed from 91 by 97 and a part passed as liquid reux by 98 to stripping zone 81 and the remainder is yielded as product therefrom and is passed by-99 to fractionation zone -6 as described later. The rate of flow of liquid lighter hydrocarbon components through 98 is controlled by flow controller 100 w-hich is operatively connected to an orifice means by 101 upstream in 98 and -by 102 to motor valve 103 downstream in 98. The fiow of liquid lighter hydrocarbon components through 99 is controlled by liquid lever controller 104 on accumulator 91 which is operatively connected by 105 to motor valve 106 in 99. Thus, for example, if the liquid level in accumulator 91 should exceed a predetermined maximum value liquid level controller 104 will open motor valve 106 further thereby increasing the flow of liquid out of accumulator 91 through 97. Treated diesel fuel is removed from stripping zone 81 by 107 for storage, further processing and the like. The flow of treated (arctic) diesel fuel through 107 is controlled by liquid level controller 108 in stripping zone 81 |which is operatively connected by 109 through motor valve 110. Liquid level controller 108 and motor valve 110 operate in a manner similar to that described for liquid level controller 104 and motor valve 106.

Gasoline and lighter compounds removed from fractionation Zone 6 by 7 are at least partially condensed by cooler 111 and then passed by 112 into accumulator 113. The temperature and pressure in accumulator 113 is maintained at a magnitude such that the gasoline components are substantially liquid and lighter gases such as methane, ethane, and the like are maintained in la. substantially vaporous form. The vaporous materials are removed from accumulator 113 by 114 and out of the system. The liquid gasoline components are removed from accumulator 113 by 115 and in part passed through 116 -for storage, further processing and the like. The rate lof removal `of gasoline components through 116 is controlled by liquid level controller 117 which is operatively connected by 118 to motor valve 119 the Ioperation of which is similar to that described for liquid level controller 104 and motor valve 106. That part of the gasoline components which does not pass into 116 passes through 120 to join gasoline components in 99 and form a composite gasoline component stream 121 which passes to fractionation zone 6 to be used therein as reflux.

Generally any known crude petroleum material and mixtures of materials can be employed in this invention.

Generally, the asph-altic crude materials employed can Ihave Ia wax content up to about 2 weight percent and an asphaltic residue from about l0 toabout 35 weight percent. Such asphalt crudes include Boundary Lake crude (Canada), Western Kansas cr-ude, and the like.

Generally, the paraffin crude materials can have a wax content usually in the range of from about 2 to about l0 weight percent Iand an asphfalitic residue usually below about 5 Weight percent. Such paraflinic crudes include Milligan Creek (Canada) and Blueberry (Canada), etc.

Although any gasoline fraction can be produced by this invention those which Iare produced will generally have at most -a 400 F. end point. The treated diesel fuel produced lwill have the characteristic that it will pass, among other tests, the copper strip corrosion test: ASTM designation D-130.

The topped crude product of this invention will have ,an Initial Boiling Point of above about 500 F. and

7 Ramsbottom Carbon Residue of above about 0.5 weight percent. The API gravity at 60 F. is below about 25 and the wax content is below 4 weight percent.

The reduced crude produce of this invention will generally have a Conradson `Carbon Residue of less than crude fraction with a wax content of at least 4 weight percent, passing said light gas oil and lighter fraction from said flashing zone into a lower portion of said fractionation zone to combine the light gas oil and lighter about 0.4 weight percent. The API gravity at 60.1 F. is 5 fractions of said first and second materials for combined above about 25 and the wax content is from about 4 to fractionation thereof in said single fractionation zone, about 2O weight percent. passing said heavy gas oil fraction from said fractiona- STREAM OR ZONE Component or Con- Conduit Conduit Conduit Conduit Conduit Conduit Conduit Conduit Conduit Conduit Conduit Conduit dition 5 19 14 30 13 32 12 67 107 99 116 121 (Blend) Barrois/day 2,750 2,800 228 1, 634 1,025 `1,404 557 2,000 1,920 79 1,010 2,537 v'1omperati1ro,"r 710 675 640 070 690 655 500 410 480 100 100 100 Percent Vapor- 59 57 0 100 0 0 0 0 0 0 O API ato" Fm- 34 40 29. 7 58 19. 4 31 35, 7 43.0 43. 3 56. 0 59. 6 59. 5 Wax Content, Wt.

Percent 1. o 5. 1.8 10 0.2 N11 Nn Nn N11 Asphaltic Content, i

Wt. Percent 28.0 Nil Nil Nil 75. 0 Nil Nil Nil Nil Nil Nil Sulfur Compounds,

as S, Wt. Percent... 0.4 (l) iPassed Copper Strip Test.

Reasonable variations and modifications of this invention zone into said flashing Zone to supply additional gas tion can bemade, or followed, in view of the foregoing, oil to said flashing zone and thereby maximize the without departing from the spirit or scope thereof. amount of gas oil components removed from said flashing We Claim; Zone alongwith said reduced crude thereby improving 1. A method of combined fractionation of at least two the properties of said reduced crude for subsequent crackcrude petroleum materials without mixing the heavy coming operations, separately recovering from said fractiona ponents of the two materials, the heavy components of tion zone a topped crude product substantially free of each of the two materials being such that they cannot be heavy components present in said second material and combined without deleteriously affecting the valuable diesel and lighter fuel fractions which contain compoproperties of the heavy components of at least one of said nents from both said first and second materials and sepamaterials which comprises fractionating at least one of rately recovering from said flashing zone a reduced crude said crude materials in a single fractionation zone' to product substantially free of heavy components present produce a gasoline fraction, at least one diesel fuel fracin said first material. tion, a heavy gas oil fraction and a topped crude fraction, 4. A method of combined fractionation of at least two flashing at least one of said materials in a single flashing crude petroleum Vmaterials each having heavy components zone to produce a light gas oil and lighter fraction and a Which Cannot be combinedA with one an-other without reduced crude fraction, passing said light gas, oil and deleteriOuSly affecting the valuable properties of at least lighter fraction into a lower portion of said fractionation 40 one Of Said heavy Components which comprises fractionzone, passing said heavy gas oil fraction from said-fracating at least oneof saidmaterials in a single fractiontionation zone into said flashing zone, separately recoveration Zone tO Produce, inter alia, at leaSt one dieSel fuel ing from said fractionation zone a topped crude product fraction, a heavy gas oil fraction and a topped crude Substantially free Y0f heavy Components present in Said fraction, flashing at least `0116 Of Said materials in a Single materials charged to said flashing zone `and diesel and flashing Zone t0 PrOdIlce, interalia, a light gas oil and lighter fuel fractions which contain components from all lighter fraction, and a reduced Crude fraction, passing of said materials charged to said flashing zone and said Said heavy gas oil fraction from said fractionation zone fractionation zone, and separately recovering from said into Said llaShing Zone, paSSing Said light gaS Oil and flashing zone a reduced crude product substantially free lighter fraction from Said flashing Zone into a loWer por' of heavy components present in said crude materials tion of Said fractionation Zone, PaSSing at leaSt One of Charged to Said fractionation Zooo said diesel fuel fractions to a vapor removal zone to 2. The method according to claim 2 wherein said crude therein produce a vaporouS dieSel fuel Portion and a liquid materials charged to said fractionation zone are asphaltic diesel fuel Portion, removing Said liquid portion, cooling crudes having rthe characteristics of a wax content of up to at least a Part of Said portion and returning Said cooled about 2 weight percent and -an yasphaltic residue of from 55 Part to Said fractionation Zone, passing a diiferent Part about 10 to about 35 weight percent, said crude materials of Said liquid portion to a Stripping Zone to vaporiZe Passed to Said ashing Zone are paran Crudes having reSldual materials are than the desired diesel. the characteristics of a wax content of from about 2 to fuel Product, and removing from Said Stripping Zone a about 10 Weight percent and an asphaltioV residuo below purified liquid diesel fuel fraction containing components about 5 weight percent ofrom all of said petroleum materials charged to both 3. The method of combined fractionation of two crude Said dashing Zone and Said fractionation Zone, Separately petroleum materials without mixing the asphaltic comrecovering from Said fractionation Zone a top Crude prodponents of the two materials, the first material having uct SuhStantially free of heavy Components present in asphaltic components with a wax content of up to about Said hashing Zone, and Separately recovering from Said 2 weight percent and the second material having asphaltic 65 ilaShing Zone a reduced crude Product SuhStantially free components with a wax content ofat least about 2 weight of heavy components present in said fractionation zone. percent which high Wax components 0f Said Second ma.. 5. A mChOCl 0f COIllbIled fIaCtOIlaiOIl Of at least WO terial would deleteriously affect the desirable asphaltic crude petroleum materials each having heavy c'oInponentS properties of the low wax components of said first mate- Which are nOt and Cannot be combined with one anrial if added thereto which comprises fractionating said 7o other Without deleteriouSly affecting the valuable Propfirst material in a single fractionation zone to produce ertieS of at leaSt one of Said heavy componentS S0 Comthe gasoline fraction, at least one diesel fuel fraction, hined Which compriSeS fractionating at leaSt 'one of Said a heavy gas oi1 fraction, and ,a topped crude fraction materials in a single fractionation zone to produce a having a wax content of less than 4 weight percent, flashgasoline fraction, at least one diesel fuel fraction, a heavy ing said second material in` a single flashing zone to progas oil fraction and a topped crude fraction, flashing at least one of said materials in a single flashing zone to produce a reduced crude fraction and a light gas oil and lighter fraction, passing at least one of said diesel fuel fraction to a vapor removal zone to produce a vaporous diesel fuel portion and a liquid diesel fuel portion, removing said liquid portion, cooling at least a part of said portion and returning said cooled part to said fractionation zone as reflux, passing a different part of said liquid portion to a stripping zone to vaporize residual materials which are lighter than the desired diesel fuel product, removing from said stripping zone a purified liquid diesel fuel fraction containing components from all of said petroleum crude materials charged to both said flashing zone and said fractionation zone, passing said heavy gas oil fraction from said fractionation zone into said flashing zone, passing said light gas oil and lighter fraction from said flashing zone into a lower portion of said fractionation zone, separately recovering from said fractionation zone a topped crude product substantially free of heavy components present in said material charged to said flashing zone, separately recovering from said fractionation zone diesel fuel and lighter fractions which contain components from all of said crude petroleum materials charged o both said flashing zone and said fractionation zone, recovering from said flashing zone a reduced crude product substantially free of heavy components present in said material charged to said fractionation zone.

6. A method of combined fractionation of at least two crude petroleum materials each having heavy components which are not and cannot be combined with one :another without deleterious-ly affecting the valuable properties of at least one of heavy components so combined which comprises fractionating at least one of said mate-rials in a single fractionation zone to produce a gasoline fraction, at least one diesel fuel fraction, a heavy gas oil fraction and a topped crude fraction, flashing at least one of said materials in a single flashing zone to produce a reduced crude fraction and a light gas oil and lighter fraction, passing at least one of said diesel fuel fraction to a vapor removal zone to produce a vaporous diesel fuel portion and a liquid diesel fuel portion, removing said vaporous fraction and returning same to said fractionation zone, removing said liquid portion, cooling at least a part of said portion and returning said cooled part to said fractionation zone as reflux below the point of removal o-f said diese-l fuel fraction from said fractionation zone, passing a different part of said .liquid portion to a stripping zone to vaporize residual materials which are lighter than the desired diesel fuel product, removing from said stripping zone a purified liquid diesel fuel fraction containing cornponents from all of said petroleum crude materials charged to both said flashing zone and said fractionation zone, passing said heavy gas oil fraction from said fractionation zone into said flashing zone, passing said 4light gas oil and lighter fraction from said flashing zone into a lower portion of said fractionation zone, separately recovering from said fractionation zone a topped crude product substantially free -of heavy components present in said material charged to said flashing zone, separately recovering from said fractionation zone diesel fuel and lighter fractions which contain components from all of said crude petroleum materials charged to both said flashing zone and said fractionation zone, separately recovering from said flashing zone a reduced crude prod-uct substantially free of heavy components present in said material charged to said fractionation zone.

7. A method of combined fractionation of at least two crude petroleum materials each lhaving heavy components which cannot be combined with one another without deleteriously affecting the valuable properties of at least one of said heavy components so combined which comprises fractionating at least one of said materials in a single fractionation zone to produce, inter alia, at least one diesel fuel fraction, a heavy gas oil fraction, and a topped crude fraction, flashing at least one of said materials in a single flashing zone to produce, inter alia, a light gas oil and lighter fraction, and a reduced crude fraction, passing said heavy gas oil fraction from said fractionation zone into said flashing zone, passing said light gas and lighter fraction from said flashing zone into said fractionation zone, passing at least one of said diesel fuel fractions to a vapor removal zone to produce a vaporous diesel fuel portion, removing said liquid portion, cooling at least a part of said portion and returning said cooled part to said fractionation zone, passing a different part of said liquid portion to a stripping zone to vaporize materials which are lighter than the desired diesel fuel product, removing from said stripping zone a purified liquid diesel fuel fraction containing components Ifrom all of said crude petroleum materials charged to both said flashing zone and said fractionation zone, treating said purified liquid diesel fuel fraction from said stripping zone to convert at least one of said free and combined sulfur present to vaporous hydrogen sulfide, passing the thus treated puried liquid diesel fraction and associated vaporous hydrogen sulfide to a stripping zone to vaporize gasoline components from said diesel fraction and produce a sulfur purified diesel fraction, removing said vaporous -hydrogen sulfide and vaporous gasoline components, condensing said gasoline components, separating Ifrom said condensed gasoline cornponents said vaporous hydrogen sulfide, returning said gasoline components to said fractionation zone as reflux and recovering from said stripping zone said sulfur purified diesel fraction, separately recovering from said fractionation zone a top crude product substantially free of heavy components present in said flashing zone, and separately recovering from said flashing zone a rreduced crude prod* uct substantially free of heavy components present in said fractionation zone.

8. A method of combined fractionation of at least two crude petroleum materials each having heavy components which are not and cannot be combined with one another without deleteriously affecting the valuable properties of at least one of said heavy components so combined which comprises fractionating at least one of said materials in a single fractionation zone to produce, inter alia, at least one diesel fuel fraction, a heavy gas oil fraction, and a topped crude fraction, flashing at least one of said materials in a single flashing zone to produce, inter alia, a light gas oil and lighter fra-ction, and a reduced crude fraction passing said heavy gas oil fraction from sa-id fractionation zone into said flashing zone, passing said light gas oil and lighter fraction from said flashing zone into said fractionation zone, passing at least one of said diesel fuel fractions toa vapor removal zone to produce a vaporous diesel fuel portion, removing said liquid portion, cooling at least a part of said portion and returning said cooled part t-o said fractionation zone, passing a different part of said liquid portion to a stripping zone to vaporize materials which are lighter than the desired diesel fuel product, removing from said stripping zone a purified liquid diesel fuel fraction containing components from all of said crude petroleum materials charged to both said flashing zone and said fractionation zone, treating said purified liquid diesel fuel fraction from said stripping zone with hydrogen to convert at least one of free and combined sulfur present to vaporous hydrogen sulfide, passing the thus treated purified liquid diesel fraction and associated vaporous hydrogen sulfide to a stripping zone to vaporize gasoline components from said diesel fraction and produce a sulfur purified diesel fraction, removing said vaporous hydrogen sulfide and vaporous gasoline components, condensing said gasoline -cornpone-nts, separating from said condensed gasoline components said vaporous hydrogen sulfide, returning said gasoline components to said fractionation zone as reflux and recovering from said stripping zone said sulfur purified diesel fraction, separately recovering from said fractionation zone a top crude product substantially free of heavy components present in said flashing zone, and separately recovering from said flashing zone a reduced crude. product substantially free of heavy components present in said fractionation zone.

9. A -method of combined fractionation of at least two crude petroleum materials each having heavy components which cannot be combined with one another without deleteriously affecting the asphaltic properties of at .least one of said heavy components which comprises fractionating .at least one of said materials in a single fractionation zone to produce a gas lighter fraction, `at least one diesel fuel fraction, a heavy gas oil fraction, and a topped crude fraction, fia'shing at Ileast one of said materials ina single ashing zone to produce a reduced crude fraction and a light gas oil and lighter fraction, passing at least one of said diesel fuel fractions to a vapor removal zone and therein producing a diesel fuel portion and a liquid diesel fuel portion, removing said liquid portion, cooling at least a part of said portion and returning said cooled part to said fractionation zone, passing a different part of said liquid portion to a stripping zone to vaporous residual materia-ls which are lighter than the desired diesel fuel product, removing from said stripping zone a purified liquid diesel fuel fraction containing 4components from all of said crude petroleum materials charged to both said flashing zone and said fractionation zone, treating said purified liquid diesel fraction from said stripping zone to convert at least one of free and combined sulfur present to vaporous hydrogen sulfide, passing the thus treated purified liquid diesel fraction and associated vaporous hydrogen sulfide to a st-ripping zone to vaporize gasoline components from said diesel fraction and produce a sulfur purified diesel fraction, removing said vaporous hydrogen sulfide and vaporous gasoline components, condensing said gasoline components, separating from said condensed gasoline components said vaporous hydrogen sulfide, returning said gasoline components to said fractionation zone as refiux, recovering from said stripping zone said sulfur purified diesel fraction, passing said heavy gas oil fraction from said fractionation zone into said flashing Zone, passing said- Y materials charged to both said fiashing Zone and said fractionation zone, recovering from said flashing zone a topped crude product substantially free of heavy components present in said material charged to said fractionation zone.

References Cited bythe Examiner UNITED STATES PATENTS 2,133,070 10/1938 Youker 208-354 2,952,631 9/ 1960 Hausch 20'8-355 3,110,663 11/1963 Miller 208-361 DELBERT E. GANTZ, Primary Examiner.

H. LEVINE, Assistant Examiner. 

1. A METHOD OF COMBINED FRACTIONATION OF AT LEAST TWO CRUDE PETROLEUM MATERIALS WITHOUT MIXING THE HEAVY COMPONENTS OF THE TWO MATERIALS, WITH HEAVY COMPONENTS OF EACH OF THE TWO MATERIALS BEING SUCH THAT THEY CANNOT BE COMBINED WITHOUT DELETERIOUSLY AFFECTING THE VALUABLE PROPERTIES OF THE HEAVY COMPONENTS OF AT LEAST ONE OF SAID MATERIALS WHICH COMPRISES FRACTIONATING AT LEAST ONE OF SAID CRUDE MATERIALS IN A SINGLE FRACTIONATION ZONE TO PRODUCE A GASOLINE FRACTION, AT LEAST ONE DIESEL FUEL FRACTION, A HEAVY GAS OIL FRACTION AND A TOPPED CRUDE FRACTION, FLASHING AT LEAST ONE OF SAID MATERIALS IN A SINGLE FLASHING ZONE TO PRODUCE A LIGHT GAS OIL AND LIGHTER GAS, OIL AND A REDUCED CRUDE FRACTION, PASSING SAID LIGHT GAS, OIL AND LIGHTER FRACTION INTO A LOWER PORTION OF SAID FRACTIONATION ZONE, PASSING SAID HEAVY GAS OIL FRACTION FROM SAID FRACTIONATION ZONE INTO SAID FLASHING ZONE, SEPARATELY RECOVERING FROM SAID FRACTIONATION ZONE A TOPPED CRUDE PRODUCT SUBSTANTIALLY FREE OF HEAVY COMPONENETS PRESENT IN SAID MATERIALS CHARGED TO SAID FLASHING ZONE AND DIESEL AND LIGHTER FUEL FRACTIONS WHICH CONTAIN COMPONENTS FROM ALL OF SAID MATERIALS CHARGED TO SAID FLASHING ZONE AND SAID 